Grayscale PDF to B/W with a 40% Cyan - Best way to do this in Acrobat Pro

Hi all,

I was wondering if there was an easy action or fixup to change a Grayscale PDF which is fundamentally an image in to an even 100% K with a 40% or similar Cyan input to give it a richer black look. I know that I could probably put it in to Photoshop and tweak but my concern would be the tinted areas would have a shine through of too much Cyan and not have a neutral gray. I also have tried to colour convert but without much success. This will be printed on to a digital device.

Any help appreciated.

Tracy